Year 9 Biology The nervous system Year 9

Year 9 Biology The nervous system

Year 9 Biology Recap: The nervous system Main Function: This communication system controls and coordinates functions throughout the body and responds to internal and external stimuli. Our nervous system allows us to feel pain.

Year 9 Biology Recap: Nervous system • It consists of 2 parts: • The central nervous system consists of the brain, spinal cord (CNS), • The peripheral nervous system contain the other nerves and receptors of our body.

Year 9 Biology • • • Notes: Sympathetic nervous system Speeds up functions of the body Prepares body for emergencies Makes body alert and ready to act Diverts blood away from digestive tract Stops peristalsis Opens bronchioles – more oxygen Increases heart rate Dilates pupil – more light Increase blood flow to heart

Year 9 Biology Notes: Para-sympathetic nervous system • • Slows everything down In control when you are resting Increases blood flow to digestive tract Stimulates salivary galnds Reduces bronciole diameter- less oxygen Controls heart beat Reduces diameter of pupil

Year 9 Biology Notes: How is information transmitted? • Information passes from receptors along nerve cells called neurones. Cell body Dendrites Myelin sheath nucleus Axon • Nerve cells are long and thin to carry messages called impulses.

Year 9 Biology

Year 9 Biology Task: Draw a neuron 1. Cell body: contains nucleus & most of the cytoplasm 2. Dendrites: projections that bring impulses into the neuron to the cell body. 3. Axon: long projection that carries impulses away from cell body 1 2 3

Year 9 Biology Notes: There are 3 types of neurone: 1. Sensory neurone – carry impulse from receptor to CNS 2. Relay – connects sensory to motor 3. Motor – connects CNS to effector which makes a response. (muscle, gland)

Year 9 Biology A reflex is an involuntary response that is processed in the spinal cord not the brain. Reflexes protect the body before the brain knows what is going on. Reflex Arc

Year 9 Biology Reflex response – Draw flow of signal Stimulus >> receptor>> sensory >> co –ordinator (spinal cord) >> motor >> Effector >Response

Year 9 Biology Neurotransmitters are chemicals that transmit signals from a neuron to a target cell across a synapse (gap)

Year 9 Biology Define – Neuro-transmitter Because neurons never touch, chemical signalers called neurotransmitters must travel through the space called synapse between two neurons. Neurotransmitters Synapse (gap) (pink spheres) The message is transferred when RECEPTORS receive neurotransmitters.

Year 9 Biology Neurotransmitters

Year 9 Biology Ruler drop test • • Aim Variables Hypothesis Materials Procedure Safety Data table

Year 9 Biology Ruler drop test • Graph – comparison of response in your group • Analyse numbers etc • Conclusion of findings • Evaluation

Year 9 Biology Analysis questions to consider • 1. What happened to …………. . reaction time as he had more tries? • 2. What happened to ……………. reaction time as she had more tries? • 3. Who improved the most from the first to the fifth try? • 4. Who had the fastest reaction time? • 5. What do you think might happen if ………. . has more tries? • 6. What have you found out about reaction time so far? • 7. What else would you like to find out about reaction time?

Year 9 Biology What might we be able to find out from our investigation? • Who has the fastest reaction time in the class? • Do boys have better or worse reaction times than girls? • Do sporty people have the fastest reaction times? • Do people who play video games have the fastest reaction times? • Does the oldest person in the class have the fastest reaction time? • Do children have faster reaction times than grown ups? • If you try the reaction test every day for a week will your reaction time improve?